Meaning – The word block, refers to a string of data elements recorded or transmitted as a unit. The elements may be characters, words, or physical records. The process of putting the data into a block is called blocking, while the process of extracting data from the block, is called deblocking.
One of the advantages of blocks, is that they reduce the overheads and as a result, speed of the data handling streams. This is probably the reason why most of the file systems today, are based on a block device.
Blocking is almost universally employed when storing data to 9-track magnetic tape, NAND flash memory, and rotating media such as floppy disks, hard disks, and optical discs.